(Upper Cretaceous), Brazil - Museo Argentino de Ciencias

Rev. Mus. Argentino Cienc. Nat., n.s.
7(1): 31-36, 2005
Buenos Aires, ISSN 1514-5158
Maniraptoran theropod ungual from the Marília Formation
(Upper Cretaceous), Brazil
1
2,3
Fernando E. NOVAS , Luiz Carlos BORGES RIBEIRO
4
& Ismar de SOUZA CARVALHO
1
CONICET - Museo Argentino de Ciencias Naturales «Bernardino Rivadavia», Av. Angel Gallardo 470, Buenos
2
Aires (1405), Argentina, E-mail: [email protected]. Fundação Municipal de Ensino Superior de UberabaFUMESU/Centro de Pesquisas Paleontológicas L. I. Price. Av. Randolfo Borges Jr., n° 1.250. Universidade,
3
38.066-005, Uberaba- MG, Brazil, E-mail: [email protected]. Universidade de Uberaba-UNIUBE/Instituto de
Formação de Educadores-Departamento de Biologia, Av. Nenê Sabino, n° 1.801. Universitário, Uberaba-MG,
4
38.055-500, Brazil, E-mail: [email protected]. Universidade Federal do Rio de Janeiro, Departamento de
Geologia, CCMN/IGEO. 21.949-900 Cidade Universitária-Ilha do Fundão, Rio de Janeiro-RJ, Brazil, E-mail:
[email protected]
Abstract: A new theropod record from the Marília Formation (Late Cretaceous, Minas Gerais, Brazil) is here
described. It consists of an isolated manual ungual which exhibits derived maniraptoran features (e.g., presence of
proximodorsal lip). The ungual distinguishes by a set of unique features (e.g., dorsoventrally low and
proximodistally elongate profile in side view; block-like flexor tuberosity; proximal articular surface more dorsally
oriented than in other theropods; cutting «keel» located distally on ventral surface) suggesting that the animal that
produced it was a member of an unknown group of derived maniraptoran theropods, other than alvarezsaurids,
deinonychosaurians and oviraptorosaurians already recorded in South America.
Key words. Theropoda, Maniraptora, Cretaceous, Marília Formation, Brazil.
____________
The fossil record of Cretaceous theropod dinosaurs from Brazil is currently restricted to few
incompletely known taxa. The Lower Cretaceous
(?Albian) Santana Formation yielded the most
complete and comprehensive theropod materials,
including the spinosaurid Irritator challengeri (Martill
et al., 1996; Kellner & Campos, 1996; Sues et al.,
2002), the compsognathid Mirischia asymmetrica
(Naish et al., 2004), and the maniraptoriform
Santanaraptor placidus
(Kellner, 1999, 2001). Also coming from the
Santana Formation is a theropod sacrum originally described as possibly oviraptorosaurian
(Frey & Martill, 1995), but doubts have been rised
about the correct assignment of this fragmentary
specimen (Makovicky & Sues, 1998).
The Upper Cretaceous theropod record from
Brazil is scarce, the only named taxon is the
abelisaurid Pycnonemosaurus nevesi, collected
from Upper Cretaceous strata of Mato Grosso
(Kellner & Campos, 2002). Occurrences of
theropod remains from Northern Brazil include
some teeth, vertebrae and unguals from the São
Luís Basin (Alcântara Formation, Cenomanian;
Medeiros, 2001; Vilas Bôas et al., 1999). In regard with the Bauru Group, an inland basin partially covering the Brazilian states of São Paulo,
Paraná, Mato Grosso do Sul, Minas Gerais and
Goiás (Fig. 1), has yielded a variety of
saurischian remains (e.g., bones, teeth, eggs and
eggshells; Bertini, 1996; Bertini et al., 1993;
Magalhães Ribeiro & Ribeiro, 1999; Magalhães
Ribeiro, 2000). However, evidence on theropod
dinosaurs is restricted to isolated teeth presumaly
belong-ing to Carcharodontosauridae (collected
from Serra da Galga; Kellner & Campos, 1998),
as well as teeth and skull fragments referred as to
Abelisauridae indet. (Bertini, 1996).
In particular, excavations carried on at levels
of the Marília Formation exposed at Serra do
Veadinho, yielded abundant titanosaurid bones
(Campos & Kellner, 1999). Despite the frequency
of well preserved sauropod remains, only some
isolated theropod elements (mainly teeth, fragment of distal end of a femur, isolated pedal phalanges) have been found at the moment.
We aim to improve the meager theropod
record of the Upper Cretaceous Marília Formation with the study of an isolated manual ungual,
the morphology of which reveals that the taxonomic diversity of South American theropod faunas was higher than expected.
Geology
The Bauru Basin accumulated sediments of
the Cretaceous Bauru Group, which is divided
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Revista del Museo Argentino de Ciencias Naturales, n. s. 7 (1), 2005
into three formations (from the bottom to top):
Adamantina, Uberaba, and Marília (Fernandes
& Coimbra, 1996). From these units, the Marília
Formation has offered the most comprehensive
collection of dinosaur remains. It consists of a
sequence of coarse to conglomeratic sandstones,
mudstones and carbonate levels (Soares et al.,
1980), corresponding to alluvial fans, braided flu-vial
systems, alluvial plains and ephemeral lakes
deposited under a hot and dry climate (Goldberg
& Garcia, 2000). The age of these deposits, based
on charophyte and ostracod fossil records, is probably Maastrichtian (Dias-Brito et al., 2001).
SYSTEMATIC PALEONTOLOGY
Dinosauria Owen, 1852
Theropoda Marsh, 1881
Coelurosauria Huene, 1920
Maniraptora Gauthier, 1986
Gen. et sp. indet.
Horizon and Locality: The fossil level corresponds to beds of the Serra da Galga Member of
the Marília Formation (Maastrichtian, Upper
Cretaceous). Serra do Veadinho (Lat. 19° 43'
25,5'’ S, Long. 47° 44' 45,4'’ W), Peirópolis,
Municipal-ity of Uberaba, Minas Gerais State,
Brazil (Fig. 1).
Repository. CPPLIP (Centro de Pesquisas
Paleontológicas «L.I.Price») number 659.
Description of specimen.The ungual (Figs. 2 &
3) is well preserved, but lacks its distal extremity. It
is 55mm long at the outer curvature. Proximally, the
bone is 13,7mm deep and 8mm wide. The size of
the bone indicates that the animal that pro-duced
the ungual was comparatively small and slender,
probably reaching 2m long, if compared with
Oviraptor philoceratops, for example.
The ungual almost probably belongs to the
manus because it is widely curved (approximately
95 degrees; curvature of the ungual was calcu-lated
following the method described by Ostrom, 1969),
transversely
compressed,
with
slightly
asymmetrically arranged colateral grooves, and
most important, the proximal articular facet is
dorsally oriented and bears a proximodorsal lip. This
combination of features is absent in the-ropod pedal
unguals, including the specialized one of digit 2 of
deinonychosaurian theropods (e.g., Ostrom, 1969;
Novas & Pol, 2005). We ten-tatively interpret the
ungual as corresponding to either manual digits II or
III because of its de-gree of curvature and presence
of proximodorsal lip (frenquently present in digits 2
and 3 of maniraptoran theropods). The ungual
shows signs
of a slight assymmetry: proximally, the left articular facet is more reduced than the right one,
as well as the left colateral groove is located
slightly below with respect to the right one. Comparing with the assymmetrical manual ungual of
digit I of Megaraptor (Novas, 1998; Calvo et al.,
2004), we tentatively interpret the ungual from
Brazil as belonging to the right hand.
The ungual is elongate, dorsoventrally low,
and sharply pointed in side view. The proximal
articular facet bears a strong vertical ridge, and it
is clearly delineated from adjacent surfaces. This
is rectangular in shape, with the right facet
(presumably the outer one) larger than the left
(i.e., the inner one). This possibly reflects an
assymmetrically arranged distal gynglimoid of the
corresponding penultimate phalanx. A transversely wide lip is present on the proximodorsal
margin of the ungual. The flexor tubercle is adjacent to the ventral border of the articular facet.
It is block-like, ventrally flat and slightly rug-ose.
The proximal surface of the tuberosity is smooth
and «saddle-shaped» (i.e., transversely convex
and slightly concave dorsoventrally).
Deeply excavated grooves are present on both
left (i.e., medial) and right (i.e., lateral) surfaces,
extending from the base of the proximal articu-lar
facet to the distal extremity of the phalanx. Albeit the
medial groove is dorsoventrally nar-rower than the
lateral one, they are almost sym-metrically situated
near the ventral edge of un-gual. The medial groove
bears some vascular channels spreading almost
tangentially towards the proximal end of the bone.
Besides, the distal extremity of ungual exhibits, on
both sides, some slight, crescent-shaped marks of
unknown ana-tomical significance (Fig. 2, cm).
Except for its distal third, the ventral surface
of ungual is flat and clearly distinguished from the
sides of the bone through sharp edges. The
ventral surface bears longitudinal striations and
some tiny foramina situated approximately at mid
-length of ungual. Notably, the distal third of the
ventral surface forms a sharp cutting edge or
«keel», proximally preceeded by a conspicu-ous
elliptical foramen.
In cross section, the ungual has a roughly «8shaped» contour, a pattern that keeps at different levels even close to its distal extremity.
Comparisons and discussion. None of the currently theropod lineages recorded in the Cretaceous of South America (e.g., Abelisauroidea,
Megaraptor
namunhuaiquii,
Spinosauridae,
Alvarezsauridae; Carrano et al., 2002; Coria et al.,
2002; Charig & Milner, 1997; Novas, 1996, 1997,
1998; Calvo et al., 2004) exhibit the combination of
features as described for the ungual from Brazil.
Novas, Borges Ribeiro & Carvalho - Cretaceous theropod ungual from Brazil
33
Fig. 1. Geological map of the Cretaceous Baurú Basin, Brazil, indicating fossil locality (Peirópolis).
On the contrary, the set of characters described
above are only documented in a restrictive group of
derived
maniraptoran
theropods,
including
oviraptorosaurs, Microvenator celer, troodontids,
dromaeosaurids, and birds (Rauhut, 2003). For
example, ungual lips are pronounced among
Elmisauridae (e.g., Chirostenotes, Elmisaurus) and
in the basal oviraptorosaur Microvenator (Currie,
1990). Proximodorsal lips are also present in
Troodontidae (Osmólska & Barsbold, 1990), but not
uniformly in all manual unguals.
Lips are also present in early birds, being Archaeopteryx an oustanding example (Wellnhofer,
1988, 1993). Also, manual unguals of digits II and
III of Deinonychus (Ostrom, 1969) exhibit proximodorsal lips, although less developed than in
the above mentioned taxa. In the therizinosauroid Alxasaurus a lip is present on the ungual
of digit II (Russell & Dong, 1993). Proximal lips
are absent in manual unguals of Compsognathus
(Ostrom, 1978) and Ornitholestes (Rauhut, 2003).
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Revista del Museo Argentino de Ciencias Naturales, n. s. 7 (1), 2005
Fig. 2. Theropod ungual in A, proximal, B, right (lateral) view, and C, left (medial) views. Abbreviations: cm, crescent-shaped marks; ft, flexor tuber.
However, the flexor tuber in the Brazilian
specimen is proportionally lower than the proximal articular surface, in contrast with troodontids, dromaeosaurids, and birds in which the
height of the tuber exceeds half the height of the
articular facet (Rauhut, 2003).
Following this, the specimen under study may
represent a non-paravian maniraptoran more
derived than Ornitholestes and Alvarezsauridae.
The ungual from Brazil superficially resembles
some oviraptorosaurs (e.g., elmisaurids) in being
elongate and dorsoventrally depressed, but the
absence of proximally bifurcated grooves, that
characteristically occur in elmisaurids (Currie,
1990), dissmiss referal of the isolated ungual to
this theropod clade.
In most theropods (e.g., Allosaurus, elmisaurids, deinonychosaurians, basal birds), the
flexor tuberosity forms a ventrally convex promi-
nence. In the ungual of Brazil, instead, the flexor
tuberosity is shallower and is almost continuous
with the ventral margin of ungual.
Several non-avian maniraptorans have been
recorded in South America (e.g., Alvarezsauridae,
possible
Oviraptorosauria,
Deinonychosauria;
Novas, 1996, 1997; Novas & Puerta, 1997; No-vas
& Agnolín, 2004; Novas & Pol, 2005; Frank-furt &
Chiappe,
1999).
Despite
the
apomorphic
resemblances with maniraptorans, the ungual from
Brazil lacks features seen in these groups: for
example, alvarezsaurids retained only one large
ungual on digit 1 (Novas, 1996), the mor-phology of
which is quite different from that of the ungual here
described. In reference with deinonychosaurians
(i.e., troodontids and dromaeosaurids) they have
strongly curved, tren-chant unguals on digits 1-3,
that are easily dis-tinguished from the ungual from
Brazil in its
Novas, Borges Ribeiro & Carvalho - Cretaceous theropod ungual from Brazil
35
Chagas Filho de Amparo à Pesquisa do Estado do
Rio de Janeiro (FAPERJ), Conselho Nacional de
Desenvolvimento Científico e Tecnológico (CNPQ,
grant nº 300571/03-8), and Agencia Nacional de
Promoción Científica y Técnica (Buenos Aires, grant
nº PICT 13803). The fossil analysed in this study
was recovered by the field crew of the Fundação
Municipal de Ensino Superior de Uberaba -Centro
de Pesquisas Paleontológicas L. I. Price (Peirópolis,
Uberaba). The drawings pre-sented in this paper
were prepared by Ariel Milani Martine, Luiz Antonio
Sampaio Ferro, and Marcelo Adorna Fernandes
(UFRJ).
BIBLIOGRAPHY
Fig. 3. Theropod ungual in A, left (medial) and B,
right (lateral) views.
major degree of transverse compression and development of the ventral tuberosity. Finally,
oviraptorosaurs (e.g., Clark et al., 1999) show
unguals that, albeit less curved than in deinonychosaurs, are dorsoventrally deeper than in
the ungual under study.
Moreover, several unique features, absent in
the maniraptoran clades listed above, distinguish
the ungual from Brazil: lateral profile dorsoventrally low and proximodistally elongate; block-like
flexor tuberosity, almost continuous with the
ungual ventral margin; proximal articular sur-face
more dorsally oriented than in other the-ropods;
proximodorsal lip transversely wide; and ventral
surface flat but with a cutting «keel» lo-cated
distally.
In sum, the bizarre features present in the
studied ungual strongly suggest that it may represent a new example of derived maniraptorans
unknown so far in this continent, not necessar-ily
belonging to the currently recognized the-ropod
clades.
ACKNOWLEDGEMENTS
We thank Leonardo Salgado for his valuable
review of the manuscript. Financial support was
provided by Fundação de Amparo à Pesquisa do
Estado de Minas Gerais (FAPEMIG), Instituto
Virtual de Paleontologia / Fundação Carlos
Bertini, R.J. 1996. Evidencias de Abelisauridae
(Carnosauria: Saurichia) do Neocretáceo da Bacia
do Paraná. Simpósio Sobre o Cretáceo do Brasil, 4,
Rio Claro, SP, 1996. UNESP. pp. 267-271.
Bertini, R.J., L.G. Marshall, M. Gayet & P.M. Brito.
1993. Vertebrate faunas from the Adamantina and
Marília formations (Upper Bauru Group, Late Cretaceous, Brazil) in their stratigraphic and paleobiogeographic context. Neues Jahr. Geol. und
Paläont. Abh. 188(1): 71-101.
Calvo, J.O., J.D. Porfiri, C. Veralli, F.E. Novas, & F.
Poblete. 2004. Phylogenetic status of Megaraptor
namunhuaiquii Novas based on a new specimen
from Neuquén, Patagonia, Argentina. Ameghi-niana
41(4): 565-575.
Campos, D. & A. Kellner. 1999. On some sauropod
(Titanosauridae) pelves from the continental Cretaceous of Brazil. National Science Museum Monographs (Tokyo), 15: 143-166.
Carrano, M.T., S.D. Sampson, & C.A. Forster. 2002.
The osteology of Masiakasaurus knoplferi, a small
abelisauroid (Dinosauria: Theropoda) from the Late
Cretaceous of Madagascar. Jour. Vert. Paleont.
22(3): 510-534.
Charig, A.J. & A.C. Milner. 1997. Baryonyx walkeri, a
fish-eating dinosaur from the Wealden of Surrey.
Bull. Nat. Hist. Mus. London 53(1): 11-70.
Clark, J.M., M.A. Norell & L.M. Chiappe. 1999. An
oviraptorid skeleton from the Late Cretaceous of
Ukhaa Tolgod, Mongolia, preserved in an avianlike
brooding position over an oviraptorid nest. Amer.
Mus. Nov. 3265: 1-36.
Coria, R.A., L.M. Chiappe & L. Dingus. 2002. A new
close relative of Carnotaurus sastrei Bonaparte
1985 (Theropoda: Abelisauridae) from the Late
Cretaceous of Patagonia. Jour. Vert. Paleont. 22(2):
460-465.
Currie, P. 1990. Elmisauridae. 245-248. In: D.B.
Weishampel, P. Dodson & H. Osmolska (eds.) . The
Dinosauria, University of California Press, Berkeley, 733 pp.
Dias-Brito, D., E.A. Musacchio, J.C. Castro, M.S.A.S.
Maranhão, J.M. Suárez & R. Rodrigues. 2001.
Grupo Bauru: uma unidade continental do Cretáceo
no Brasil - concepções baseadas em dados micro-
36
Revista del Museo Argentino de Ciencias Naturales, n. s. 7 (1), 2005
paleontológicos, isotópicos e estratigráficos. Rev.
Paleobiol. 20(1): 245-304.
Fernandes, L.A. & A.M. Coimbra. 1996. A Bacia Bauru
(Cretáceo Superior, Brasil). Anais Acad. Bras.
Ciênc. 68(2): 195-205.
Frankfurt, N. G. & L.M. Chiappe. 1999. A possible
Oviraptorosaur from the Late Cretaceous of Northwestern Argentina. Jour. Vert. Paleont. 19(1): 101105.
Frey, E. & D. Martill. 1995. A possible oviraptorosaurid
theropod from the Santana Formation (Lower Cretaceous, ?Albian) of Brazil. N. Jb. Geol. Paläont.
Mh. 7: 397-412.
Goldberg,
K.
&
A.J.V.
Garcia.
2000.
Palaeobiogeography of the Bauru Group, a
dinosaur-bearing Cretaceous unit, northeastern
Paraná Basin, Brazil. Cret. Res. 21: 241-254.
Kellner, A.W.A. 1999. Short note on a new dinosaur
(Theropoda, Coelurosauria) from the Santana Formation (Romualdo Member, Albian) northeastern
Brazil. Bol. Mus. Nac., Nova Serie, Rio de Janeiro
49: 1–8.
- 2001. New information on the theropod dinosaurs
from the Santana Formation (Aptian–Albian),
Araripe Basin, northeastern Brazil. Jour. Vert.
Paleont. 21(Suppl. 3): 67A.
Kellner, A.W.A. & D.d.A. Campos. 1996. First Early
Cretaceous theropod dinosaur from Brazil. Neues
Jahr. Geol. und Paläont. Abh. 199: 151–166.
- 1998. Review of cretaceous theropods and sauropods from Brazil. Jour. Vert. Paleont. 18(Suppl. 3):
55A
- 2002. On a theropod dinosaur (Abelisauria) from
the continental Cretaceous of Brazil. Arquivos
Mus.Nac.Rio de Janeiro 60(3): 163-170.
Magalhães Ribeiro, C.M. 2000. Microstructural analysis of dinosaur eggshells from Bauru Basin (Late
Cretaceous), Minas Gerais, Brasil. First International Symposium on Dinosaur Eggs and Babies
(Abstracts), pp. 117-121.
Magalhães Ribeiro, C.M. & L.C.B. Ribeiro. 1999. Um
ovo de dinossauro em sucessões fluviais da
Formação Marília (Cretáceo Superior), em Peirópolis (Uberaba, Minas Gerais). Boletim de
Resumos do 6° Simpósio de Geologia do Sudeste,
São Pedro, p. 76.
Makovicky, P.J. & H.-D. Sues. 1998. Anatomy and
phylogenetic relationships of the theropod dino-saur
Microvenator celer from the Lower Creta-ceous of
Montana. Amer. Mus. Nov. 3240: 1–27.
Martill, D.M., A.R.I. Cruickshank, E. Frey, P.G. Small &
M. Clarke. 1996. A new crested maniraptoran
dinosaur from the Santana Formation (Lower Cretaceous) of Brazil. Jour. Geol. Soc., 153: 5–8.
Medeiros, M.A.A. 2001. A Laje do Coringa (Ilha do
Cajual, Bacia de São Luís, Baía de São Marcos,
MA):
conteúdo
fossilífero,
bioestratinomia,
diagênese e implicações na paleobiogeografia do
Mesocretáceo do Nordeste brasileiro. Univ.Fed. Rio
Grande do Sul. Tese de Doutorado. Programa de
Pós-Graduação em Geociências, pp.1-107.
Naish, D., D.M. Martill & E. Frey. 2004. Ecology, systematics and biogeographical relationships of dinosaurs, including a new theropod, from the
Santana Formation (?Albian, Early Cretaceous) of
Brazil. Hist. Biol. 2004: 1–14.
Novas, F. 1996. Alvarezsauridae, Cretaceous maniraptorans from Patagonia and Mongolia. Queensland Museum Memoirs 31: 320-351.
- 1997. Anatomy of Patagonykus puertai (Theropoda,
Avialae, Alvarezsauridae), from the Late Cretaceous of Patagonia. Jour. Vert. Paleont. 17(1): 137166.
- 1998. Megaraptor namunhuaiquii gen. et sp. nov.,
a large-clawed, Late Cretaceous Theropod from
Argentina. Jour. Vert. Paleont.18(1): 4-9.
Novas, F.E. & F. Agnolín. 2004. Unquillosaurus ceibali
Powell, a giant maniraptoran (Dinosauria, Theropoda) from the Late Cretaceous of Argen-tina.
Rev. Mus. Arg. Cienc. Nat. «B.Rivadavia»
6(1): 61-66.
Novas, F. & P. Puerta. 1997. New evidence concern-ing
avian origins from the Late Cretaceous of Patagonia. Nature 387: 390-392.
Novas, F.E. & D. Pol. 2005. New evidence on deinonychosaurian dinosaurs from the Late Cretaceous of Patagonia. Nature 433: 858-861.
Osmólska, H. & R. Barsbold. 1990. Troodontidae. 259268. In: Weishampel, D.B., P. Dodson and H.
Osmolska (eds.). The Dinosauria, University of
California Press, Berkeley, 733 pp.
Ostrom, J.H. 1969. Osteology of Deinonychus antirrhopus, an unusual theropod from the Lower
Cretaceous of Montana. Bull. Peabody Mus. Nat.
Hist. 30: 1-165.
- 1978. The osteology of Compsognathus longipes
Wagner. Zitteliana 4: 73-118.
Rauhut, O.W.M. 2003. The interrelationships and evolution of basal theropod dinosaurs. Spec. Pap.
Palaeont. 69: 1–213.
Russell, D., & Z. Dong. 1993. A nearly complete skeleton of a new troodontid dinosaur from the Early
Cretaceous of the Ordos Basin, Inner Mongolia,
People’s Republic of China. Can. Journ. Earth Sci.
30: 2163-2173.
Soares, P.C., P.M.B. Landim, V.J. Fulfaro & A.F. Sobreiro
Neto. 1980. Ensaio de caracterização estratigráfica do
Cretáceo no Estado de São Paulo: Grupo Bauru.
Rev. Bras. Geociências 10(3): 177-185.
Sues, H.-D., E. Frey, D.M. Martill & D.M. Scott. 2002.
Irritator challangeri, a spinosaurid (Dinosauria:
Theropoda) from the Lower Cretaceous of Brazil.
Jour. Vert. Paleont. 22: 535–547.
Vilas Bôas, I., I.S. Carvalho, M.A. Medeiros, & H. Pontes. 1999. Dentes de Carcharodontosaurus (Dinosauria, Tyrannosauridae) do Cenomaniano, Bacia
de São Luís (Norte do Brasil). An. Acad. Bras.
Ciênc. 71(4): 846-847.
Wellnhofer, P. 1988. Ein neues Exemplar von Archaeopteryx. Archaeopteryx 6: 1-30.
-
1993. Das siebte Exemplar von Archaeopteryx aus den
Solnhofener Schichten. Archaeopteryx 11: 1-48.
Recibido: 02-V-2005
Aceptado:01-VIII-2005